Skip to main content

Health condition · Clinically reviewed

Head lice, wet combing, dimethicone - and why it is never about hygiene.

Common, harmless and treatable. The right method, done fully, clears it - and no child needs to miss a day of school for it.

Jump to treatment
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, the British Association of Dermatologists and UKHSA guidance you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including dimethicone-first treatment, wet combing, and no school exclusion.

Key facts

Head lice at a glance.

The essentials, in plain English - what they are, how they spread and how UK families treat them today.

  • What it is

    Infestation of the scalp with Pediculus humanus capitis, an obligate blood-feeding ectoparasite. Not a sign of poor hygiene.

  • How common

    Very common in children aged 4 to 11, with up to 30% affected during outbreaks. Uncommon in adults except within households.

  • How it spreads

    Direct head-to-head contact - fomite (hats, brushes, pillows) transmission is uncommon in real-world studies.

  • Not a health risk

    Head lice do not transmit disease. Impact is itch, sleep disturbance and social distress rather than infection.

  • Diagnosis

    A live louse found on wet combing with a fine-tooth detection comb is the only diagnostic finding - nits alone are not enough.

  • First-line therapy

    Wet combing (Bug Busting) or dimethicone 4% lotion. Repeat treatment is essential - one application is rarely enough.

Why this guide matters

The method, not the panic.

Most treatment failures are not resistance - they are missed repeat steps and blanket household treatment. Three principles change outcomes.

  • Diagnose before you treat

    Never treat on itch alone. A live louse on wet detection combing is the only diagnosis worth acting on - it saves families from months of unnecessary product.

  • The repeat step is the treatment

    Every effective option, chemical or physical, has a second step 7 to 13 days later. Missing that step is the single biggest reason infestation returns.

  • No shame, no exclusion

    Head lice are not a hygiene issue and do not cause disease. UK guidance is explicit - children stay in school, families stay calm.

How the diagnosis is made

From an itchy scalp to a confirmed plan.

The steps a UK GP, school nurse or pharmacist will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    Scalp check and history

    When did the itch start, who else at home or school is affected, and what has already been tried.

  2. 02

    Assessing

    Wet detection combing

    The gold-standard test - conditioner-soaked hair combed in sections with a fine-tooth detection comb. A live louse confirms.

  3. 03

    Assessing

    Distinguish nits from active infestation

    Empty egg cases stay stuck to the hair long after treatment. Only viable eggs within 6mm of the scalp and live insects mean active disease.

  4. 04

    Confirming

    Look for complications

    Excoriation, impetiginisation and occasional posterior cervical lymphadenopathy - treated on top of the lice themselves.

  5. 05

    Confirming

    Screen household contacts

    Everyone in the household is wet-combed. Only those with live lice are treated - blanket treatment is not recommended.

  6. 06

    Planning

    Plan the treatment cycle

    Whichever method is chosen, plan the repeat step now - day 1 and day 7 for lotions, or days 1, 5, 9 and 13 for wet combing.

  7. 07

    Planning

    Follow-up detection combing

    A repeat wet-comb 2 to 3 days after the final treatment confirms clearance. If live lice remain, switch method rather than repeat the same product.

Typical timeline: from suspicion to clearance in about two weeks.

Symptoms

What head lice actually look like.

Itch, nits on the hair shaft and live insects on wet combing - and the complications that mean more than lice alone.

  • Itching scalp

    Often the first symptom - but it can be delayed 2 to 6 weeks in a first infestation while sensitisation builds.

  • Nits on the hair shaft

    Small pale eggs cemented to the hair. Viable eggs sit within 6mm of the scalp - further out, they are almost always empty.

  • Live lice on wet combing

    Adult lice and nymphs seen on the comb are the diagnostic finding - the only truly reliable proof of active infestation.

  • Excoriation and crusts

    Scratch marks, weeping and small crusts behind the ears and at the nape - the classic distribution.

  • Impetiginisation

    Secondary bacterial infection with honey-coloured crusts and pustules - treated with antibiotics alongside the lice.

  • Posterior cervical lymphadenopathy

    Occasional small tender nodes at the back of the neck, driven by scalp inflammation rather than systemic infection.

  • Household clustering

    Siblings, parents and close contacts often share infestation - the reason group detection combing matters.

  • Red flag - painful spreading crusts

    Painful, hot, rapidly spreading crusted areas suggest bacterial superinfection or another diagnosis - get seen.

Treatment

How head lice are treated in the UK.

Wet combing or dimethicone first, ivermectin lotion or oral treatment when the physical options fail - always with a properly timed second step.

  • Wet combing (Bug Busting)

    Non-chemical, evidence-based first line - fine-tooth detection comb through wet, conditioner-treated hair on days 1, 5, 9 and 13.

  • Dimethicone 4% lotion

    Physical silicone-based treatment (Hedrin) - coats and suffocates lice. Apply, leave as directed, then repeat after 7 days.

  • Isopropyl myristate and cyclomethicone

    Another physical treatment (Full Marks Solution) - dissolves the waxy louse cuticle. Two applications, 7 days apart.

  • Permethrin and malathion

    Older neurotoxic insecticides - out of favour in the UK because of widespread resistance. Reserved for specific circumstances.

  • Topical ivermectin 0.5% lotion

    A newer selective option (Sklice) - useful when physical treatments have failed and resistance is suspected.

  • Oral ivermectin

    Specialist-only for refractory or severe cases, or where topical treatment cannot be tolerated. Weight-based dosing.

  • Treating household contacts

    Only contacts with live lice on detection combing are treated. Blanket treatment of an entire family is not recommended.

  • Antibiotics for secondary infection

    Impetiginised scalp or infected excoriations need a topical or oral antibiotic alongside the lice treatment itself.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, pharmacist or school nurse knows your family and can tell you which parts apply to you. If in doubt, get seen.

  • NICE Clinical Knowledge Summary. Head lice.

  • British Association of Dermatologists (BAD). Patient leaflet on head lice.

  • UK Health Security Agency (UKHSA). Head lice guidance for schools and parents.

  • Public Health England (legacy) and NHS England. Head lice - no school exclusion policy.

Red flags

When head lice need more than a pharmacy visit.

Most infestations are cleared at home. These are the situations that warrant a GP, school nurse or dermatology conversation.

  • Painful spreading crusted scalp

    Widespread honey-coloured crusts, pain and fever suggest impetigo or cellulitis - antibiotics are needed alongside lice treatment.

  • Recurrent infestation despite treatment

    Repeat active infestation after two full treatment cycles points to resistance, missed contacts or an incomplete cycle - reassess in primary care.

  • Very young infant with scalp lesions

    True head lice are uncommon in babies. A crusted or vesicular scalp in an infant may be another condition and deserves review.

  • Immunocompromised child or adult

    Standard treatment usually still works, but complications like impetiginisation are more likely - lower the threshold for GP contact.

  • Severe distress or school avoidance

    Persistent bullying, shame or school refusal warrants school-nurse and GP involvement - it is a wellbeing issue, not a hygiene one.

  • Suspected scabies rather than lice

    Itch worse at night, burrows on the wrists and finger webs, and family-wide itch point to scabies - a different problem with different treatment.

  • Suspected seborrhoeic dermatitis

    Greasy scale with itch but no live lice on combing is not head lice - dandruff and seborrhoeic dermatitis are treated differently.

  • Persistent posterior cervical nodes

    Lymph nodes that stay enlarged after the scalp settles need a face-to-face review to rule out other causes.

  • Repeated whole-household infestations

    Serial reinfestation across a household or classroom is a public-health issue - loop in school health for coordinated combing.

Living with it

A common problem, with a settled routine.

Four things families tell us make the biggest difference - regular combing, calm framing, no school exclusion, and switching method when a cycle fails.

A quiet reminder

Finish the cycle, then check again.

The commonest reason head lice come back is stopping too early. Detection-comb 2 to 3 days after the last step to confirm clearance.

  1. 01 Routine

    Wet-comb regularly during outbreaks

    A weekly detection comb during a school outbreak catches infestation early, when a single treatment cycle still clears it.

  2. 02 Talk

    It is not about cleanliness

    Head lice prefer clean hair as much as unwashed hair. Naming the science defuses the shame that keeps families quiet.

  3. 03 School

    No exclusion, no panic

    UK guidance is clear - children with head lice stay in school. Treatment starts that evening, life carries on as usual.

  4. 04 Escalate

    Switch method if it is not working

    Two failed cycles of the same product means switching class of treatment - resistance is real, and repeating what did not work rarely helps.

Frequently asked

Everything we get asked about head lice.

Quick answers on diagnosis, wet combing, dimethicone, contacts and school.

  • How do you actually diagnose head lice?

    The only reliable diagnosis is finding a live, moving louse on wet detection combing - a fine-tooth comb pulled through conditioner-treated hair in sections. Nits (empty eggs cases stuck to the hair) can persist for months after successful treatment and are not proof of active infestation.

  • Do head lice spread from hats, brushes and pillows?

    Rarely. Head lice need warmth and blood and die quickly off the scalp. Real-world studies show almost all transmission is direct head-to-head contact - the deep clean of soft furnishings, hats and bedding is not required.

  • What is the best first treatment?

    For most families, either wet combing (Bug Busting) on days 1, 5, 9 and 13, or a dimethicone 4% lotion repeated after 7 days. Both are effective. The choice depends on hair length, patience and preference.

  • Why did the treatment not work?

    Almost always because the repeat step was missed - one application never kills the eggs that hatch later. Resistance to older insecticides (permethrin, malathion) is also common in the UK. If two full cycles of the same product fail, switch to a different mechanism rather than trying again.

  • Should the whole family be treated?

    No. Everyone in the household should be wet-combed to check for live lice, but only those with a confirmed active infestation are treated. Blanket treatment of a whole household wastes product and drives resistance.

  • Should my child stay off school?

    No. UK guidance from the UK Health Security Agency and NHS England is clear that children with head lice should not be excluded from school. Treatment starts at home that evening, and normal life continues.

Related content

Keep reading.

Pulse Healthcare concierge

Send us your enquiry

A concierge service for UK private healthcare. We match you with the best vetted clinics and consultants in our network - they then contact you directly.

So we can match you to the right clinician close to you.

We reply to every enquiry within 24 hours (Mon–Fri). Confidential - your details are never shared outside our vetted consultant network.